A wide variety of polyurethanes are known in the art. Characteristics of individual polyurethanes are dictated by the various needs for them. It is known that polyurethanes which are cured with glycols do not have great tear strength. This would limit their use for soft foams, low speed tires, typewriter roll covers and printing plates. Certain members of the diamine series have been utilized as curing agents; the resulting vulcanizates have good tear strength but tend to be hard. Consequently, it has been difficult to produce a cured polyurethane which has superior tear strength but at the same time is soft.